Can restricting while-in-bed smartphone use improve sleep quality via decreasing pre-sleep cognitive arousal among Chinese undergraduates with problematic smartphone use? Longitudinal mediation analysis using parallel process latent growth curve modeling

Problematic smartphone use (PSU) has become a global public health problem. Excessive while-in-bed smartphone use may result in poor sleep quality. The present study aimed to examine whether restricting while-in-bed smartphone use can improve sleep quality and the mediating role of pre-sleep cognitive arousal in this process. A total 152 Chinese undergraduates with symptoms of PSU (Smartphone Addiction Scale-Short Version [SAS-SV] > 31) were recruited and randomly assigned to the intervention group (N = 76) and the control group (N = 76) for a 4-week follow-up experiment. Sleep quality (assessed by the Pittsburgh Sleep Quality Index) and pre-sleep cognitive arousal (assessed by the Pre-sleep Arousal Scale-Cognitive Arousal) were measured at baselime, Week1, Week2, Week3, and Week4. The longitudinal mediation model was analyzed using parallel process latent growth curve modeling. The significance of indirect effect was tested by 95% biascorrected accelerated confidence intervals on the basis of 5000 bootstrap samples. The initial level of sleep quality was positively associated with the initial level of pre-sleep cognitive arousal. The intervention decreased pre-sleep cognitive arousal and increased sleep quality. The slope of pre-sleep cognitive arousal was positively associated with the slope of sleep quality. The mediating effect of pre-sleep cognitive arousal was significant. Restricting while-in-bed smartphone use can improve sleep quality via decreasing pre-sleep cognitive arousal among Chinese undergraduates with symptoms of PSU. These results suggests that restricting while-in-bed smartphone use is a potential remedy for sleep disturbance induced by PSU.